Eye Diseases of Saltwater Fish

Aquarium saltwater fish are susceptible to any number of infections. Some infections can attack the eyes and cause vision problems, blindness and death. Many of these optical disorders can be treated by isolating the fish in a separate aquarium and using medicated dips. However, some eye issues can be symptoms of more threatening illnesses.

  1. Exophthalmia

    • Exophthalmia, or "pop eye disease," is characterized by a buildup of fluid behind the eyes. This disorder pushes the eyeballs farther and farther out of their eye sockets. If the illness is left untreated the eyes will detach and the fish will lose its vision. The disorder can be caused by a vitamin A deficiency, poor water quality, injury or by a bacterial infection. There are several methods of treating the disease. First, the water quality should be checked with a water test kit to see if there are elevated nitrate or ammonia levels. This is especially important if more than one fish is showing symptoms of exophthalmia. If this is the case, Aquarium Life recommends removing and replacing 30 percent of the water for four or five days to see if the condition improves. Another method of addressing pop eye is by moving the fish to an isolation tank and adding one tablespoon of Epsom salt to every five gallons of water in the fish's temporary aquarium. Epsom salts help by drawing the excess fluid out of the eye. An antibiotic called Maracyn can also be used if the infection is caused by a bacteria. Adding vitamin A to the fish's diet can also often solve the problem.

    Tuberculosis

    • Tuberculosis is a disease caused by the bacterium Mycobacterium piscium. It is characterized by dark patches that appear on the eyes and on the body. The fish may also experience a loss of scales, discoloration and ulceration. The body may become twisted and deformed in the later stages. The disease is caused by poor water quality and overcrowded tank conditions. Vitamin B-6 and Kanamycin can be used to treat the disease; however, the success rate in treating tuberculosis is low. The fish may need to be humanely killed to avoid infecting other members of the saltwater community.

    Marine Ich

    • Marine ich is a common disease in saltwater fish. It is caused by a parasite called Cryptocaryon irritans. Fish with this disease often have cloudy eyes, loss of appetite and frayed fins. They also have white spots covering their bodies. The disease can often be caused by poor water quality, overcrowding and high levels of ammonia, but it can also occur when an infected fish is added to the tank. Ich is treated by using a copper solution. It is important to remove any animals being treated with copper because the mineral can kill any scaleless fish and coral in a reef tank. The disease is also treatable by using a medicated formalin dip.